I know of a lot of indie games that are actually really good, and I’m hoping to find some others. Here’s my list:
- BPM: Bullets Per Minute
- Hedon
- Ion Maiden
- Prodeus
- Project Warlock
- Tower 57
- Wrath: Aeon Of Ruin If this list is incomplete, help by expanding it :)
OP asked for games that too few people have played, not for hidden gems. That is not the same. For example, compared to the 500.000 reviews Baldurs Gate 3 has on steam, Divinity: Original Sin II, despite also being one of the best rpgs, has only 150.000.
FTL, which is easily in the top 5 of the best roguelites ever made has only 50.000 reviews, which is very little compered to Hades for example, which has 200.000.
Into the breach was never really popular, it has only 15.000 reviews on steam.
If you ask most gamers about those they usually have never heard about them or at least have not played those themselves. I would not call them particularly hidden but I think they deserve to be played by more people and that is what OP asked about.